I have never fed mine directly. I started with a piece of 'rubble rock' which was a stick with slime on the end. Around a year and a half later I have a 10+ head duncan. I don't run a skimmer so I have more food in the water column....but I just wanted to share my experience. I just feed my fish...I don't feed my corals anything. If they get something it is by chance and whatever is in the water column.
Year and a half ago, or maybe a bit less? Can't remember exactly. It was around when I joined so not much before June 2012
Just now, not the greatest angle. I did not feel like sticking my hand in and moving it for a better pic. 8 large heads, 3-4 smaller ones